全文获取类型
收费全文 | 329篇 |
免费 | 12篇 |
专业分类
化学 | 263篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 19篇 |
物理学 | 51篇 |
出版年
2021年 | 5篇 |
2020年 | 10篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 16篇 |
2012年 | 20篇 |
2011年 | 21篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 22篇 |
2007年 | 19篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 17篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1997年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1933年 | 2篇 |
1921年 | 2篇 |
1913年 | 2篇 |
1911年 | 2篇 |
1906年 | 2篇 |
1905年 | 2篇 |
1904年 | 3篇 |
1902年 | 3篇 |
1901年 | 5篇 |
1897年 | 2篇 |
1892年 | 2篇 |
1884年 | 4篇 |
1883年 | 2篇 |
1882年 | 3篇 |
1880年 | 4篇 |
1878年 | 3篇 |
排序方式: 共有341条查询结果,搜索用时 312 毫秒
71.
72.
Souheila Lassoued Régis Gautier Jean-François Halet 《Journal of organometallic chemistry》2010,695(7):987-272
The bonding and structural arrangement in a few representative ring- or chain-containing solid-state metal borides and borocarbides are analyzed with respect to the electron count of the non-metal entities. Similarities (and differences) with molecular analogs are emphasized. 相似文献
73.
Comparisons between LIBS and ICP/OES 总被引:3,自引:0,他引:3
In the framework of the development of new techniques, the ability of laser-induced breakdown spectroscopy (LIBS) to analyse
remotely complex aqueous solutions was investigated. The jet configuration with a collimated gas stream was chosen because
it appeared to be the most promising method for the LIBS probe, particularly in terms of sensitivity and repeatability. For
emission collection, the echelle spectrometer offers a simultaneously recorded wavelength range from the UV to the near IR
and is interesting for multielemental analysis for LIBS and also for inductively coupled plasma (ICP) optical emission spectroscopy
(OES). The importance of parameters influencing the quantitative results of LIBS such as multispecies analysis, sheath gas,
use of an internal standard and temporal parameters for analysis is described. LIBS quantitative data have been directly compared
with results from the more standard ICP/OES technique. 相似文献
74.
Gautier Stauffer 《Mathematical Methods of Operations Research》2018,88(3):445-473
In this paper, we consider k-echelon extensions of the deterministic one warehouse multi-retailer problem. We give constant factor approximation algorithms for some of these extensions when k is fixed. We focus first on the case without backorders and we give a \((2k-1)\)-approximation algorithm under general assumptions on the evolution of the holding costs as products move toward the final customers. We then improve this result to a k-approximation when the holding costs are monotonically non-increasing or non-decreasing (which is a natural situation in practice). Finally we address problems with backorders: we give a 3-approximation for the one-warehouse multi-retailer problem with backlog and a k-approximation algorithm for the k-level Joint Replenishment Problem with backlog (a variant where inventory can only be kept at the final retailers). Ours results are the first constant approximation algorithms for those problems. In addition, we demonstrate the potential of our approach on a practical case. Our preliminary experiments show that the average optimality gap is around 15%. 相似文献
75.
76.
77.
Ohne Zusammenfassung 相似文献
78.
E. Gautier J. Marrero R. Servant 《Journal of Radioanalytical and Nuclear Chemistry》1989,135(5):333-340
An analytical method, SSMS, for the determination of trace impurities in cobalt is described. This element is used as raw material for the production of60Co in Embalse Nuclear Power Station. Tin, aluminum, lead, silicon, molybdenum, calcium, vanadium, boron, chromium, zirconium, tungsten, nickel, magnesium, iron, zinc and copper were determined. Manganese, analyzed by AAS, was used as an internal standard. The measurements were semiquantitative. The accuracy of the results was compared with that of emission spectrography and atomic absorption spectrometry, the agreement was found to be satisfactory. 相似文献
79.
Interface delocalization or depinning transitions such as wetting or surface induced disorder are considered. At these transitions, the correlation length for transverse correlations parallel to the surface diverges. These correlations are studied in the framework of Landau theory. It is shown the t–1/2 at all types of transitions for systems with short-range forces wheret measures the distance from bulk coexistence. 相似文献
80.
We have evaluated the in vivo correlation between the expression of cell cycle markers and skin tumor development in SKH-1 hairless mice in a complete photocarcinogenesis protocol. Irradiated mice developed an average of 16 tumors per animal by week 23 with the average number of carcinomas per mouse being 2.1. The expression of p53 and cyclins A and D1 was confined initially to sporadic single cells and gradually developed into foci of patchy intense staining in the basal and granular layers of UVB-exposed epidermis. p53 was expressed in all the papilloma sections examined, whereas cyclins D1 and A were expressed in 68 and 71% of these lesions, respectively. In UVB-induced squamous cell carcinomas (SCC), p53 was expressed in >90% of the tumors, whereas cyclin D1 was detected in 55% of the lesions, and cyclin A staining was limited to 27%. These immunohistochemical observations were confirmed by Western blotting and protein kinase assays. We observed an early wave of cyclin A overexpression and cyclin A protein kinase activity preceding the appearance of detectable tumors. Cyclin D1 and p53 overexpression were coupled with the development of tumors, and these changes are likely to be relevant to the pathogenesis of these lesions. 相似文献